JP2711371B2 - Gas diffusion mechanism of cylindrical surface combustion burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gas diffusion mechanism in a cylindrical surface combustion burner in which a combustion layer is formed in a cylindrical shape.

[0002]

2. Description of the Related Art As one of infrared heating devices expected to be applied in a wide range of fields, such as cooking and heating of food and drying of painted objects, a surface combustion burner using an inexpensive and high-calorie gas fuel as a heat source is used. is there.

A surface combustion burner efficiently converts thermal energy of a fuel gas, which is mostly carried away, into radiant heat by convection in normal combustion. Air is burned from one side of a gas-permeable combustion layer. The fuel and the fuel gas are mixed in advance, and the mixture is burned in the other surface layer, thereby heating the surface layer of the burner itself to emit radiant heat.

[0004] Among such surface combustion burners, those using a metal sintered plate or a ceramic plate as a material for a combustion layer have already been put to practical use in several fields such as cookers. Further, recently, a study using a fiber mat obtained by sintering fire-resistant fibers such as metals and ceramics in layers has been actively conducted.

[0005] A surface burning burner using a fiber mat can realize excellent characteristics such as large area, low pressure loss, high burnup, and high power density by selecting a material having a high porosity for the mat layer. It also has the advantage that a shaped combustion surface can be formed.

[0006]

However, in the prior art as described above, when the combustion layer is formed in a cylindrical shape,
The following problems occur. First, when the combustion layer is flat, the fuel gas flows relatively efficiently by providing a gas-permeable diffusion plate near the fuel gas inlet when the fuel gas flows into the space closed by the combustion layer. It can be uniformly supplied to the combustion layer.

However, when the combustion layer is formed in a cylindrical shape, the space to which the fuel gas is to be supplied is surrounded by the 360 ° combustion layer, and the fuel gas inlet position and the gas charging direction are restricted. For this reason, the combustion gas is partially diffused in a non-uniform state, and as a result, uneven combustion occurs and the surface burner cannot exhibit its original performance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a fuel gas diffusion mechanism capable of eliminating uneven combustion in a cylindrical surface combustion burner.

[0009]

SUMMARY OF THE INVENTION The gas diffusion mechanism of the present invention is used for a surface combustion burner having a combustion layer in which a fibrous layer having combustion resistance and air permeability is formed into a cylindrical shape. In order to solve the problem, a gas introduction pipe inserted into the cylinder forming the combustion layer, and a plurality of combustion gas ejection holes are arranged on the pipe surface, and between the gas introduction pipe and the combustion layer. A cylindrical diffusion member having a plurality of ventilation holes that are interposed and secondary diffuses the fuel gas ejected from the ejection holes of the gas introduction pipe and supplies the fuel gas to the combustion layer, and the diffusion member and the gas Voids are provided between the gas introduction pipe and the combustion layer, and between the diffusion member and the combustion layer.
It is characterized in that a heat-resistant fiber is filled in a gap between the diffusion member .

[0010]

According to the present invention, a gas introduction pipe is inserted into a cylinder forming a combustion layer, and fuel gas is introduced into the cylinder from a large number of ejection holes arranged substantially evenly on the pipe surface of the introduction pipe. Will be leaked. The ejection speed of the fuel gas varies depending on the number and size of the ejection holes, but if this condition is kept constant, it increases in proportion to the required burner output. Within the low output range (when the gas ejection speed is low), a relatively stable combustion state can be obtained simply by dispersing the gas inflow position over a wide range in the cylinder by the above-described introduction pipe.

[0011] However, if the combustion output is increased, is to uniformly supply the combustion gas to the entire region of the tubular body inside only inlet tube described above becomes difficult. In particular, burners that use fiber mats are one of the features that can increase the turndown ratio (ratio of the maximum output to the minimum output).
In order to sufficiently exhibit this characteristic, it is necessary to provide a diffusing member for secondary diffusion as well as primary diffusion by the above-described inlet pipe ejection hole. A tubular diffusion member made of punching metal (those that have been drilled a number of holes in the metal sheet) or the like between the inlet pipe and the combustion layer disposed, the spreading member
Air gap between the pipe and the inlet pipe and between the diffusion member and the combustion layer
By providing a bias of the combustion gases by vent diffusing member is eliminated, uniform supply of the combustion gases is achieved even when the ejection speed of the gas is high.

[0012] The secondary diffusion member is disposed between substantially the middle between the outer surface of the introduction pipe where the primary diffusion is performed and the inner surface of the combustion layer and near the inner surface of the combustion layer, and the position thereof is appropriately determined according to the combustion output. Adjusted.

When it is necessary to supply a large amount of fuel gas to a cylindrical burner or a high-output burner that is long in the axial direction, a cushion material made of a ceramic fiber or the like is provided between the introduction pipe and the diffusion member. It is desirable to fill.
Thus, the ejected fuel gas is temporarily received by the cushion material, and the unevenness is eliminated while passing through the cushion material having random voids.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a partial longitudinal sectional view of a cylindrical surface burner according to the present embodiment, and FIG. 1 (b) is a transverse sectional view of the burner of FIG. 1 (a). In the figure, a cylindrical combustion layer 1 is constituted by a fiber mat in which metal, ceramic fibers and the like are laminated in a layered manner. Inside this cylinder, a fuel gas introduction pipe 2 having an outer diameter smaller than the inner diameter of the cylinder (in the example of FIG.
) Is inserted axially, and the insertion opening is closed by an end plate. The introduction pipe 2 is provided with fuel gas ejection holes 2a arranged on the pipe surface, and is positioned so that the distance between the pipe surface and the inner surface of the combustion layer 1 is constant regardless of location.

A diffusion member 3 formed by molding a porous sheet such as a punched metal into a cylindrical shape is coaxially arranged outside the introduction pipe 2 with respect to the introduction pipe 2. The dimensions of the diffusion member are set such that the porous surface is located near the middle between the introduction pipe 2 and the inner surface of the combustion layer 1. The space between the diffusion member 3 and the introduction pipe 2 is filled with a cushion material made of ceramic fiber or the like. The filling density (porosity) of the cushion material is set according to the supply amount of the fuel gas. When the supply amount is large, the filling density is set slightly higher, and when the supply amount is relatively small, The cushion material need not be filled.

In using the burner having the above-described structure, when a fuel gas (arrow 5) mixed with air is fed into the introduction pipe 2, the fuel gas 5 is supplied to each ejection hole 2a of the introduction pipe.
Squirted from. The ejected gas 5 is supplied to the cushion material 3
Is diffused while passing through the gap, and further diffused by a large number of holes of the diffusion member 3 to be uniformly supplied to the inner surface of the combustion layer 1.

In parallel with this operation, a high voltage is applied to a spark electrode (not shown) arranged opposite to the combustion layer surface 1a, or a mixture of fuel gas and air is ignited by ignition by gas or the like. The flame is quickly propagated throughout the cylindrical fuel layer 1, and radiant heat is emitted from the heated combustion layer surface 1a.

At this time, the number of the ejection holes 2a of the introduction pipe 2, the opening pitch and the size, the number and the size of the holes formed in the diffusion member 3, the gap between the introduction pipe 2 and the diffusion member 3, the cushion, By constantly adjusting the filling density of the material in accordance with the output of the burner, uniform combustion is always realized.

In the above-described embodiment, the combustion layer is made of a fiber mat in which fibers such as metals are laminated, but the material itself of the combustion layer is not particularly limited. It is not always necessary to laminate fibers as long as the material has air permeability and combustion resistance and can be formed into a cylindrical shape. Similarly, the constituent material of the diffusion member is not limited to punched metal. Although the combustion layer is formed in a cylindrical shape in the example of FIG. 1, it goes without saying that the present invention can also be applied to a case where the cross-sectional shape of the burner is polygonal.

[0020]

As described above, according to the present invention, the inlet pipe provided with the fuel gas ejection hole is inserted into the cylinder forming the combustion layer, and a large number of pipes are provided between the inlet pipe and the inner surface of the combustion layer. Since the diffusion member having the ventilation holes is disposed, the fuel gas is sufficiently diffused in the cylinder and uniformly supplied to the combustion layer. This eliminates uneven combustion in the cylindrical surface combustion burner, which could not be solved conventionally, and increases the combustion efficiency.
Uniform and efficient heating of the target object is realized.

[Brief description of the drawings]

1 (a) is a partial longitudinal sectional view of a cylindrical surface combustion burner according to an embodiment of the present invention, and FIG. 1 (b) is a transverse sectional view of the burner of FIG. 1 (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion layer 1a Combustion surface 2 Fuel gas introduction pipe 2a Jet hole 3 Diffusion member 4 Cushion material 5 Fuel gas

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-21117 (JP, A) Jiko 63-47691 (JP, Y2)

Claims (1)

(57) [Claims] 1. A gas diffusion mechanism for a cylindrical surface combustion burner having a cylindrical combustion layer, wherein the combustion layer is made of a fiber layer having combustion resistance and air permeability, and a cylinder forming the combustion layer. A gas introduction pipe inserted into the body and having a plurality of combustion gas ejection holes arranged on a pipe surface, interposed between the gas introduction pipe and the combustion layer, and ejected from the gas introduction pipe ejection hole. A cylindrical diffusion member having a plurality of ventilation holes for secondary diffusing the supplied fuel gas and supplying the fuel gas to the combustion layer, between the diffusion member and the gas introduction pipe, and between the diffusion member and the combustion. between the layers, air gaps are provided, the gap between the diffusing member and the gas inlet, heat resistance
A gas diffusion mechanism for a cylindrical surface combustion burner, which is filled with fibers .